The invention relates to a device for tissue removal in biopsy procedures. In particular, the invention relates to a manually operated biopsy device containing an adjustable biopsy needle.
Biopsy needle devices with handpieces containing an actuating apparatus which activates the motion of a biopsy needle are known. For example, U.S. Pat. No. 4,958,625 to Bates et al. discloses a biopsy device containing a handpiece and stylet which projects independently of a cannula and wherein the handpiece contains an attachment means for the cannula. The insertion guide used in such systems includes a cannula guide made up of a hollow small tube in which the proximal end bears a trigger, and is equipped with an attachment means, as well as a luer lock for a syringe to introduce a medicament to the site after tissue removal.
Procedures using actuated biopsy needles typically involve first inserting the biopsy needle and cannula insertion guide into the patient""s body by positioning the distal end of the needle in proximity to the object to be sampled. Upon determining the desired position by magnetic resonance (CAT scan) or other technique, the stylet and cannula cutting edge are sequentially activated to obtain the sample. Once the sampling step has been performed, the attachment means are released and the biopsy needle withdrawn from the cannula insertion guide to check the sample. If the sample is incorrect or otherwise insufficient, a new biopsy needle is inserted into the cannula insertion guide and the sampling sequence is repeated. After obtaining the desired sample, a medicament can be administered to the site by applying a syringe to the insertion guide.
One disadvantage of such systems is that variation or adjustments of sample length and needle cutting stroke are not feasible, since the stylet or cannula cutting edge are not adapted to adjust feed stroke beyond the tip of the insertion guide. Control of biopsy procedures is important when the tissue to be sampled is in proximity to vital organs or bones and positioning of the insertion guide or biopsy needle is such that the feed stroke of the stylet and cannula-cutting edge can potentially further damage the vital tissues, organs or bone.
There is a need in the biopsy device field for devices having improved control capabilities to permit the practitioner to avoid unnecessary tissue damage as well as obtain tissue samples with more specific parameters.
The invention disclosed is an adjustable biopsy device having the ability to vary the size of the sample to be removed. The biopsy device includes biopsy needle assembly and cannula insertion guide co-axially aligned therewith such that longitudinal adjustment of the cannula insertion guide likewise adjusts the exposure of the stylet and cutting edge of the biopsy needle assembly thereby changing the size of the resulting sample. The cannula insertion guide is connected to the housing of the device through a longitudinal adjusting element. The invention is particularly useful in biopsy procedures where improved control over sample size and cutting stroke are desirable.
The biopsy device generally contains a biopsy needle assembly, a housing having a control device for operation of the biopsy needle assembly therein, a cannula insertion guide co-axially aligned with and accommodating a portion of the biopsy needle assembly, and a longitudinal adjusting element positioned between (and connecting) said housing and insertion guide. The longitudinal adjusting element is adapted to adjust the position of the cannula insertion guide lengthwise relative to the biopsy needle assembly of the device. The housing containing the control device is generally configured as a handpiece and the control device per se is manually operated by the user or practitioner and actuates the biopsy needle assembly therein.
The biopsy needle assembly extends beyond the distal portion of the housing and includes a perforating stylet having proximal and distal portions which is positioned within a cannula having a cutting edge. The proximal portion of the perforating stylet is coupled to and operates relative to the cannula (and cutting edge) as activated by the control device within the housing. The medial portion of the stylet extends beyond the distal portion of the housing and co-axially through both the longitudinal adjustment element and the cannula insertion guide attached thereto. The distal portion of the stylet is positioned at the distal portion of the cannula insertion guide and contains an indentation (or groove) to accommodate and retain tissue.
The cannula insertion guide comprises a proximal attachment means adapted for removable attachment to the distal portion of the longitudinal adjustment element and for internal positioning of the biopsy needle assembly of the device. The cannula insertion guide and biopsy needle assembly are configured to operatively interact with one another such that the cannula cutting edge and perforating stylet of the biopsy needle assembly function at the distal tip of the cannula insertion guide. Rapid sequential motion between the stylet and cannula cutting edge beyond the distal tip of the cannula insertion guide severs or cuts the tissue to be sampled. The extent to which the biopsy needle assembly (cannula cutting edge and perforating stylet) extend beyond the distal tip of the cannula insertion guide is controlled by the longitudinal adjusting element of the device.
The longitudinal adjustment element is positioned between (and connects) the distal portion of the housing and the proximal portion of the cannula insertion guide and contains a lumen adapted for placement of the biopsy needle assembly therein. The longitudinal adjusting element has a proximal portion and distal attachment means, the proximal portion being adapted for engagement with and movement (e.g., rotatable motion) relative to the distal portion of the housing and the distal attachment means being adapted for removable attachment to the proximal attachment means of the cannula insertion guide such that adjustment of the longitudinal adjusting element results in corresponding adjustment of the cannula insertion guide in the same direction. In operation, the adjustment of the cannula insertion guide and corresponding the distal exposure of the biopsy needle assembly controls the degree of exposure of the stylet indentation and thus controls the amount of tissue to be accommodated therein.
Thus, there is disclosed a biopsy device comprising a biopsy needle assembly having a perforating stylet within a cannula having a cutting edge; a housing having a control device for operation of the biopsy needle assembly; a cannula insertion guide co-axially aligned with and accommodating the biopsy needle assembly and having proximal attachment means; and longitudinal adjusting element positioned between the housing and cannula insertion guide and having a proximal portion and distal attachment means and a lumen adapted for placement of the biopsy needle assembly; wherein the longitudinal adjusting element is adapted to co-axially adjust the position of the cannula insertion guide relative to the biopsy needle assembly of the device.
In a further embodiment, there is disclosed a biopsy device according to the invention comprising a longitudinal adjusting element adapted for engagement with and rotational movement relative to the housing of the device. In yet another embodiment, there is disclosed a biopsy device according to the invention further comprising an indicator means for indicating position and longitudinal displacement of the cannula insertion guide relative to the housing.
There is also disclosed a method of obtaining a tissue sample having a pre-deteremined size from a tissue site using a biopsy device according to the invention comprising the steps of inserting and positioning the cannula insertion guide and biopsy needle assembly of the device in proximity to the tissue sampling site; and actuating the biopsy needle assembly to obtain the sample; wherein the sample size is determined prior to actuating the biopsy needle assembly by adjustment of the longitudinal adjusting element of the device.
The invention also includes a kit for performing biopsy procedures comprising the biopsy device according to the invention.
Among the advantages of the device according to the invention is that it permits the user or practitioner to vary needle cutting stroke and therefore vary sample size. Another advantage is that a single device can be used to obtain multiple samples of varying sizes. Yet another advantage of the invention is that unnecessary damage of tissues and organs can be avoided as a result of the improved control over the sampling procedure.